Nondetrudable safety lock



y 1949- R. ROCHA NONDETRUDABLE SAFETY LOCK Filed May 14, 1947 Patented May 10, 1949 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates to safety locks and pertains more particularly to non-detrudable improvements in night latches for doors.

The principal purpose of the invention is to provide a safety lock housing of the conventional night latch type with a new, non-detrudable, bevel-faced, spring-pressed, safety grooved main latch bolt, of relatively simple unitary construction, the bolt proper, having self-contained safety devices of simple, durable and automatically operable construction, in conjunction with a new complemental strike or keeper of unitary construction, which in the absence of extra, movable safety plates, and cams, or otherwisesuperfluous auxiliary locking parts, should positively keep and guard the main bolt of the latch from being detruded into the lock housing by a tool inserted in the normal clearance between the closed door and the jamb, particularly when the normally protruding portion of the main latch bolt is strike-confined into its complemental strike or keeper in non-locking'position in direct presence and relation to the conventionally thumb actuated, catch anchoring mechanism that normally serves to keep in inoperative position said main latch bolt of the lock; and that should afford substantial savings in manufacturing costs due to the simplicity of the design of its correlating elements, as well as new and automatically positive locking and unlocking meansrespectively, without need of having anybody disturbed to unlock the door from the inside of the premises, and without need of having the key-movable main latch of the lock exposed to be pried open by anyone unauthorized to do so, thus increasing the usefulness and security of the improved lock without incorporating with it a number of otherwisesuperfluous lock parts.

A recommended embodiment of the invention is shown in the accompanying drawing, but it will be understood that the structural details of the mechanism herein illustrated and described may be varied to suit particular conditions and installations without departing from the essence of the invention defined in the appended claims.

In the drawing,

Fig. 1 is a plan view of the improved nondetrudable safety look as attached to the inside of a closed door;

Fig. 2 is a side elevation of the lock, with a portion of the lock housing proper cut away and with the strike or keeper shown in section.

Fig. 3 is an isometric view of the strike or keeper.

Fig. 4 is an isometric view of the lock portion,

the lock in inverted position, so as to further show some of the principal external details of the outer bevel faced extreme and the counterinclined surface of the safety groove of the main latch bolt respectively, with which-the invention is'particularly concerned.

The improved and non-detrudablesafetylock comprises the lock H which is securely attached to the inside of the door I2 and which'may be of the conventional thumb actuated catch anchoring mechanism type, having a novel, pressure reciprocatin'g, main latch bolt l3 which is relatively spring pressed, and movable to inoperative position by the knob l4 and held anchored either closed or open by the usual thumb-catch knob l5; and a complemental strike or keeper l6 having a flange l'l securely attached to the lamb l8 and adapted to receive and'prote'ct in conjunction with the side walls 25, 25 the outer beveled face [9 and the boundary 22 of the safety groove 20 of the main latch bolt l3 as shown inFig; 2.

These parts maybe of any desired size, shape or construction in complemental relation to each other and the internal mechanism of the lock proper is immaterial to the present invention which is particularly concerned with counteracting the substantially applied principle of the Wedge, with the structural arrangement of the complementally safety grooved surfaces of the normally protrudingportion of the mainllatch bolt I3 which in its whole finished state is unitary construction, and with the substantial safety providing structural arrangement of the complementally shaped surfaces of the corresponding and co-operating strike'or keeper 16, which is also unitary construction respectively.

The main latch bolt I3 is a reciprocating, spring-pressed, tough piece of metal, having an outwardly beveled face learn; a safety groove 20 which is sufllciently deep from the transverse edges 22-24 thereof toward the opposite side of the bolt l3 and adapted to be directly in front of the normal clearance 26 between the closed door l2 and the jamb 18 so as to impede a tool foreign to the lock (such as a table knife or the like) when inserted thereinto from detruding the main latch bolt 3 into the lock housing, thus 'keepingthe main latch bolt positively locked in non-returnable position as long assuch' a tool be exerting a pressurein intimate contact against the relatively' inwardly inclinedjsurfacev of the safety groove 20 which normally has the edges 22-44 in parallelism to'the outer edge Zl of the bolt (Fig. 4); As here shownKFig; 2) the edges 22-44 of the safety groove 20 which are on the normally external surface and across the width of the latch bolt l3 respectively, are adapted to be protected by the side walls 25-25 and the internal base 28 of the strike or keeper H: as well as by the side walls 29-29 and the internal base 39 of the lock housing respectively.

The edges 22-2t are thus adapted to be normally unexposed to the width of the normal clearance 26 of the closed door i2 between the flanged face I l of the strike It and the face 23 of the lock II respectively. The complemental strike or keeper It is a co-operating receptacle of unitary construction, preferably of tough cast metal, adapted to receive and protect the outer beveled face I!) and the edge 22 of the safety groove 28 by the partly cylindrical external surfaces of the impact bar 2! which is an eminence of the top wall of the strike that extends and depends integrally from the external side of one of the walls 25 toward the external side of the opposite wall 25 in parallelism to the outer edge of the internal base 28 and at a distancefrom the corners 3!, 3| of the side walls 25, 25, so that when the door is being closed, the edge 22 of the safety groove 2% is prevented from coming. in contact with the impact bar 25 at any time, which is also of prime importance so as to facilitate the easy sliding of the beveled face it? of the latch bolt into the mouth of the strike or keeper l6 which has the flanged face ll securely attached to the jamb 18.

The pressure reciprocating, spring-pressed latch bolt 23 has the usual plurality of internally protruding, stop-alinement eminences 32 (only one shown in Fig. 2), and the usual fork-like, spiral spring holder extreme, and a spiral spring within the lock housing (not shown in the drawing) normally impelling outwardly from the lock housing the beveled face [9. of the bolt I3 and the counter-inclined surface of the safety groove 2%] which normally has the inward edge 24 permanently disposed within the lock housing, at a distance from the external edges of the opening of the mouth of the face 23 of the lock housing, being thus protected from being exposed directly to the front of the normal clearance between the closed door and the jamb, thus affording simple, comfortable and positive means of protection against having the safety grooved main latch bolt [3 of the improved look I i, detruded by a tampering tool as hereinbefore specified.

Having now described my invention, and in what manner it is performed and used, what I claim is:

1. A latch for a door or the like, comprising a spring pressed bolt having a fiat side and a smooth inclined striking face extendingrearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to. its main locking position, and wherein the inclined striking face of the bolt and the counterinclined surface thereof are each of a width similar to the width of the opposite or flat side of the bolt respectively.

2. A latch for a door or the like, comprising a spring pressed bolt having a fiat side and a smooth inclined striking face extending rearwardly from said fiat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to its main locking position, and wherein the inclined strikiil ing face of the bolt and the counterinclined surface thereof are disposed at obtuse angles to each other respectively.

3. A latch for a door or the like, comprising a spring pressed bolt having a flat side and a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to its main locking position, and wherein the dimensional length of the inclined striking face of the bolt is greater than the corresponding length of the counterinclined surface thereof.

4. A latch for a door or the like, comprising a spring pressed bolt having a flat side and a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing. when the bolt is fully projected therefrom to its main locking position, and wherein the inclined striking face of the bolt is steeper than the counterinclined surface thereof.

5. A latch for a door or the like, comprising a spring pressed bolt having a flat side and a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to its main locking position, and wherein the counterinclined surface of the bolt is disposed thereon in such way so as to be adapted to be presented in the path of an implement inserted between the edge of a door and the frame thereof.

6. A. latch for a door or the like, comprising a spring pressed bolt having a flat side and. a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to its main locking position.

7. A latch for a door or the like, comprising a spring pressed bolt having a fiat side and a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom to its main locking position, and wherein the counterinclined surface of the bolt is adapted to arrest a relative unlocking movement of the bolt by means of supplemental. pressure exerted against the counterinclined surface proper.

8. A latch for a door or the like, comprising a spring pressed bolt having a flat side and a smooth inclined striking face extending rearwardly from said flat sicle, wherein a single smooth and counterinclined surface slopes directly from the whole rear boundary of theinclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefromtoits main locking position,

9. A latch for a door or the like, comprising a spring pressed bolt having a flat side and a smooth inclined striking face extending rearwardly from said flat side, wherein a single smooth and counterinclined surface slopes directly from the Whole rear boundary of the inclined striking face thereof to terminate inside of the latch housing when the bolt is fully projected therefrom, as hereinbefore described.

RAFAEL ROCHA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Winn et a1. Mar. 14, 1916 Number Number Number 

